I want to download SFM but i dont have enough disk space. I'm only going to make Dota 2 movies and I think SFM is 15 GB because there are a lot of characters n stuff in it so is there any way i can only download Dota 2 stuff? Thank a lot :)

Nope, Dota 2 isn't a feature of SFM proper. It's an add on after the program is downloaded. So, what you have to do is DL SFM, then add Dota2.

Now that being said, I think to install SFM from scratch the download is 3.2 gigs. After it installs, the base program (Stuff in the SFM Folder) takes 14.1 Gigs of disk space (without the DOD download content) but I've extracted the TF2 VPKs to get the latest items too. So, it may be a little bit less but not much. I would not suggest deleting any of this because SFM is relient on the download pack and will reinstall everything if you have to validate the game cache.

My Dota2 extracted folder is 42.2 Gigs on the disk. This is just models, materials, sounds and particles (no maps!!!).

So if your machine is balking at the SFM download, you might want to invest in another harddrive or an external that you can plug into and assign it to be a Steam drive....